Possibly been discussed previously but I though worth mentioning, especially after my test of the new GS App this morning. See the below document that provides a very good description of this issue. The problem is very noticeable here in Auckland, and will be less so on the West Coast of the USA, even less in the Mid-West. Most of Western Europe probably not effected (see map on document to check your area). http://www.ianwood.com/docs/dji-phantom ... nation.pdf I tested the App this morning and it works fine. However the declination problem toilet bowling was quite extreme after launch, and she moved in some very wide arcs (~10m radius) until the Naza got a handle on things. Quite risky if there are any obstacles around. Note that the learning curve for the Naza can be shortened considerably of you manually maintain a fixed point hover after launch for about a minute (whether you are planning to fly autonomously or manually). All credit to Ian Wood for posting the explanation. None to DJI for not bothering to fix it.